TDA8385 Datasheet, PDF (2/21 Pages) NXP Semiconductors – Control circuit for a Self-Oscillating Power Supply SOPS

Philips Semiconductors
Control circuit for a Self-Oscillating
Power Supply (SOPS)
Preliminary specification
TDA8385
BLOCK DIAGRAMS
handbook, full pagewidth
current reference
setting
feed forward
input
regulation indicator
output
differential amplifier
output
VP _GND
16 14
3 ^I ref
REFERENCE
BLOCK
2
I _ref
Vref
13 ^Vfo
latch
STABILIZED
SUPPLY
1
VP _(min)
DETECTOR
reset
28
Vstab
SUPPLY REFERENCES
(28, 27, 23)
I
1 RIO
11 ^V diff
V _ts
29
REGULATION
INDICATOR
X
7
Vmv
DIFFERENTIAL AMPLIFIER
Vref
(2.5 V)
V _diff
V _ts
3
feedback voltage
input
9 ^Vfb
transistor-on
setting input
4 ^Ton(min)
slow start voltage
input
7 ^Vss
50 µA
CLAMP
V _TCG
TCG
2.5 V
4
MINIMUM
VOLTAGE
CLAMP ₆
CONTROL PART _III
5
Vss + Ton _(min)
50 µA
charge
19
reset (28)
quick
discharge
27
SLOW START
VII
MCD417
Fig.1 Block diagram; part A (continued in Fig.2; part B).
March 1994
3